We’ve heard a lot of rumors in the last year, but now Barnes & Noble has finally unveiled its first official plans for taking its Nook tablets and e-readers to markets outside of the U.S. Today it announced that it will be launching the devices, starting first with the e-readers, in the UK in October, along with a new UK online storefront for the Nook digital bookstore (2.5 million digital titles) and “partnerships with leading retailers” to sell them.

The move comes as B&N’s arch rival Amazon gears up to launch the Kindle Fire in the UK — in a deal with leading book retailer Waterstones that includes other Kindle devices as well as e-books. Both the Kindle Fire and the Nook are built on forked versions of Google’s Android OS.

Prior to Amazon announcing a Waterstones agreement, many had thought that B&N would partner with the UK bookseller itself as a way of getting its Nook line of readers and tablets into the UK market. The CEO of Waterstones had publicly praised Waterstones, and reviled Amazon as a devil.

In the absence of a Waterstones deal, B&N now promises “partnerships with leading retailers,” although it has yet to specify any names. It also says that pricing for the Nook readers and tablets will be revealed closer to the date of commercial launch.

Amazon already offers its Kindle e-readers in a number of global markets, and in that sense this is about B&N catching up: “The first products to be available when the company begins offering its products in the UK in mid-October,” it notes, “include Barnes & Noble’s line of…E Ink Readers, NOOK Simple Touch and NOOK Simple Touch with GlowLight.”

The company does not specify when its tablets will be entering the mix.

B&N has for months now been building up its presence in the UK and the rest of Europe, so this may well be a first-move into the rest of the region. In March, the company incorporated in Germany and started to hire there. It has also been running events to cozy up to Android developers in the UK — although in the absence of local billing, and more concrete details on device launches here, that perhaps hasn’t been as buzzy as B&N would have hoped.

The company is due to report its quarterly earnings this week, and all eyes will be on how well its digital and device strategies are holding up, in the wake of people reading less paper books and general problems that have befallen other traditional booksellers like Borders.

Judging by how B&N has marketed the Nook in the U.S., its retail partnerships in the UK will be key to how well it does here. The company doesn’t have any physical stores of its own, and yet its sales strategy in the U.S. has been heavily based on promoting the devices in-store, creating reading areas and offering users free reading time while in the retail location. Whether it will take the same approach here has yet to be made clear. But again the fact that Waterstones, the biggest physical bookseller in the UK, is not going to be among those stocking it will inevitably be a setback in that sense.

The Nook tablet has less than 5% of the U.S. market for tablets at the moment, according to IDC. B&N says that it has sold “millions” of Nook devices to date.